Fundamental
differences between the California Sister and the Arizona Sister

(Adelpha californica vs. Adelpha
eulalia)

Over
the years, there have been several butterfly enthusiasts who have inquired about
the differences between the Arizona Sister and the California Sister. The
purpose of this short article is to discuss as well as to illustrate their most
basic, consistent differences.

As
shown on the images below, the ventral hindwing of the California Sister (Adelpha
californica,) has a lavendar background as opposed to the blue
background of the ventral hindwing of the Arizona Sister (Adelpha eulalia.)

Furthermore,
if you look at the upper corner (adjacent to thorax) of the ventral hindwing,
you'll see clearly that A. californica has two orange bars (one
smaller than the other) and that A. eulalia only has one longer orange
bar in the discal cell in the basal area.

Also, if you take a look at the vhw cream-white bands of both taxa, the Arizona
Sisterclearly shows a continuous slim blue line on the outer edge of the
band. At the same time, if you look at the same area of the California
Sister, you will see that the same vhw lavender line is only intermittent.
These differences, having looked a long series of both taxa, appear to be
diagnostic as opposed to being individual variation.